{"instruction": "You are an expert in named entity recognition. Please extract entities that match the schema definition from the input. Return an empty list if the entity type does not exist. Please respond in the format of a JSON string.", "schema": ["Chemical"], "input": "Oil - based nanofluid containing surfactant - capped magnetite nanoparticles are synthesized by a simple coprecipitation approach , and their magnetorheological properties are studied for different magnetic field strengths and volume fractions ."}
{"Chemical": []}